Based on this finding, we propose to conduct a pilot study to obtain information on safety and initial data on efficacy of the drug combination Fansidar for the treatment of ALPS. Six to 8 individuals, with ALPS who report no allergy to sulfa drugs will be treated for up to 3 months with weekly Fansidar at escalating doses adjusted by weight. The effect of Fansidar treatment on lymph node and/or spleen size will be assessed by CT scanning. The effect of treatment on other laboratory features of ALPS will also be assessed. Evaluating the effects of Fansidar on these clinical and laboratory parameters will allow us to determine if this drug demonstrates sufficient activity to warrant further study in a larger randomized controlled trial.